THE ADVENTURES OF SEBASTIAN COLE is yet another nostalgic coming-of-age high-school movie, but it's better than most. Its success is largely due to the smoldering, heartthrobby Adrian Grenier as Sebastian, a rebellious would-be '80s beatnik. Sebastian is the kind of kid who gets terrible grades but scores 1520 on his SATs, a punkish aspiring writer eager for adventure. Grenier's performance layers cocky, sullen charm over deep confusion about Sebastian's shattered family.

In a twist that is meant to set the film apart from its ilk, early on Sebastian's hippie stepfather, Hank, announces his plans for a sex change. He wants to stay married to Sebastian's mother, but she's devastated and flees to her native England, taking Sebastian with her. He's miserable there, though, and returns to their small upstate New York town to move in with Hank, now Henrietta, who turns out to be the only stable, empathetic adult in Sebastian's life.

Though she sometimes tries to be a hard-ass disciplinarian, Henrietta is deeply empathetic toward her stepson, and often can't help taking his side against the buffoons who run his high school. In one of the film's funniest scenes, the principal tells Sebastian he can't graduate because he's failing gym. He and Henrietta concoct a lie on the fly about Sebastian's extracurricular expertise in karate. The principal arranges a demonstration in front of a tribunal of somber-faced PE instructors, which he bluffs his way through brilliantly. Such tiny alliances against the rest of the world give the movie a real poignancy.

Like last year's Whatever (also set outside New York City in the '80s), The Adventures of Sebastian Cole is much richer and more authentic than the glut of other teen films currently crowding theaters. Sebastian's foibles will be familiar to anyone who grew up as a bad kid with a good heart--doing Whip-Its in the supermarket, getting older losers to buy booze, sneaking into the city to go to a punk club. Unlike idiotic teen fare like Jawbreaker and the current Detroit Rock City, high school here isn't a hermetically sealed universe, and Sebastian knows that life is much, much bigger than the tiny world he's stuck in. We know that if he can just hold on until graduation, he'll be more than fine.

But while the film has a refreshing, bittersweet intelligence, Henrietta's character is so clumsily drawn that she often seems like a gimmick. The main problem is that Henrietta's gender dysphoria is horribly underdeveloped. One never gets a sense of why he wants to be female--as a woman, she continues to act (and look) perfectly butch, pining for Sebastian's mom, walking and talking like a man and beating up a harasser in a scene that, while satisfying, feels false. Though it's commendable that she's not saddled with any shrill Birdcage campiness, there needs to be some sense of struggle in her character to make her come alive. As it is, she often just ends up being a tool of Sebastian's self-realization. When you're a teenager, of course, it's impossible to imagine that the adults around you have their own inner lives. The Adventures of Sebastian Cole captures the moment between solipsistic adolescence and broader maturity. Unfortunately, it sometimes also embodies it.

The Adventures of Sebastian Cole (R; 112 minutes), directed and written by Tod Williams; photographed by John Foster and starring Adrian Grenier, opens Friday at the Towne Theater in San Jose.